How do i unproject a depth image to world coordinate ?

[peter_s_2]

Is there any function or opensource that can unproject depth image to camera space or world space?

I want to transform the depth image to point cloud and show on computer.

Thanks for your attention.

[Alexey_V_Intel · Accepted solution]

A function ProjectDepthToCamera uses for unprojection a cloud of points from depth image to world. "The world coordinates uses the camera coordinate system. The values are in mm." (chapter 6.14.2.8 of sdkmanual).

But if you want to unproject to world whole depth image, make sense to use QueryVertices. "The QueryVertices function calculates the vertices from the depth image. The vertices contain the world coordinates in mm." (chapter 6.14.2.11 of sdkmanual).

[peter_s_2]

I use "QueryVetices" and get result which i want. Thanks a lot.

[Thanh_Binh_T_]

I used ProjectDepthToCamera for unprojection a point cloud within a Region of Interest, defined by xbegin, ybegin, width and height as follows,

but I do not get a dense 3Dpoints for a scene, where my face is at a distance of 50cm.

I really do not know, if my code is wrong? or F200 provides no dense 3Dpoints. Could you please help me? Thanks

   bool convertDepthToWorldCS(int xbegin, int ybegin, int width, int height)
   {
      unsigned int xend   = xbegin + width;
      unsigned int yend   = ybegin + height;

      unsigned int wxhDepth = width * height;

      // create the array of depth coordinates + depth value (posUVZ) within the defined ROI
      PXCPoint3DF32* posUVZ = new PXCPoint3DF32[wxhDepth];
      pxcU16 *dpixels       = (pxcU16*)depth.planes[0];
      unsigned int dpitch   = depth.pitches[0]/sizeof(pxcU16); /* aligned width */
      if (posUVZ)
      {
         for (unsigned int yy = ybegin, k = 0; yy < yend; yy++)
         {
            for (unsigned int xx = xbegin; xx < xend; xx++, k++)
            {
               posUVZ.x = (pxcF32)xx;
               posUVZ.y = (pxcF32)yy;
               posUVZ.z = (pxcF32) dpixels[yy * dpitch + xx];
            }
         }
       }
      // convert the array of depth coordinates + depth value (posUVZ) into the world coordinates (pos3D) in mm
      PXCPoint3DF32* pos3D = new PXCPoint3DF32[wxhDepth];
      if (_projection->ProjectDepthToCamera(wxhDepth, posUVZ, pos3D) < PXC_STATUS_NO_ERROR)
      {
         delete [] posUVZ;
         delete [] pos3D;
         return true;
      }
      delete [] posUVZ;
      delete [] pos3D;
      return false;
   };